Air discharge structure for motorcycles

ABSTRACT

A motorcycle has a front wheel suspended on a front portion of a vehicle frame, a rear wheel suspended by a rear wheel suspension mounted on a rear portion of the vehicle frame, a fuel tank mounted on an upper portion of the vehicle frame, an engine mounted on a lower portion of the vehicle frame, a radiator disposed forwardly of the engine, a radiator cover covering the radiator and having an air discharge port for discharging air from the radiator rearwardly of a vehicle body, and side covers disposed in a position facing the air discharge port and covering both side areas between the fuel tank and the engine, the side covers being contiguous to the rear wheel suspension. Air discharged from within the radiator cover can be drawn out by ram air that flows along side surfaces of the side covers, so that an excessive temperature rise in the radiator cover is prevented from being developed. Because the side covers are disposed so as to be contiguous to the rear wheel suspension, they are highly blended with each other for an improved appearance.

1. TECHNICAL FIELD TO WHICH THE INVENTION PERTAINS

[0001] The present invention relates to an air discharge structure for amotorcycle.

2. DISCUSSION OF BACKGROUND ART

[0002] There has been known an air discharge structure for a motorcyclewhich has a radiator cover. See, for example, Japanese Patent Laid-openNo. 2000-118464 (pages 2 to 4, FIG. 1, hereinafter “patent document 1”).

[0003]FIG. 1 of patent document 1 will be described below with referenceto FIG. 8 shown below. The reference numerals are assigned anew. FIG. 8is a side elevational view showing a conventional air dischargestructure for a motorcycle. A side area of a radiator 101 is coveredwith a radiator cover 102, which mixes discharged air from the radiator101 and fresh air introduced from an inlet port defined in an upperfront portion of the radiator cover 102, and emits the mixed airrearwardly of the radiator cover 102. The reference numeral 104represents a horizontally opposed engine, and 105 carburetors forsupplying a fuel to the horizontally opposed engine 104.

[0004] The radiator cover 102 is effective to utilize hot air from theradiator 101 and improve the appearance by covering the side area of theradiator 101. However, if there is not much ram air available, thensince a high temperature rise occurs in the radiator cover 101, it isnecessary to promote the discharging of air from within the radiatorcover 102.

[0005] As the radiator cover 102 is shaped to cover the side area of theradiator 101 and only part of the carburetors 105 behind the radiator101, the radiator cover 102 leaves the rear carburetors 105 exposed andis not effective enough to improve the appearance. Particularly, onAmerican-type motorcycles (called “custom motorcycles”), the radiatorcover 102 does not match surrounding parts in appearance, and isrequired to be better blended and harmonized with the engine, thevehicle frame, and the fuel tank around the radiator cover 102.

SUMMARY OF THE INVENTION

[0006] It is an object of the present invention to improve an airdischarge structure for a motorcycle for promoting the discharging ofair from within a radiator and improving the appearance thereof.

[0007] To achieve the above object, and according to a first aspect ofthe invention, there is provided an air discharge structure for amotorcycle having a front wheel suspended on a front portion of avehicle frame, a rear wheel suspended by a rear wheel suspension mountedon a rear portion of the vehicle frame, a fuel tank mounted on an upperportion of the vehicle frame, an engine mounted on a lower portion ofthe vehicle frame, a radiator disposed forwardly of the engine, and aradiator cover covering the radiator and having an air discharge portfor discharging air from the radiator rearwardly of a vehicle body,wherein a side cover is disposed in a position facing the air dischargeport and covers a side area between the fuel tank and the engine, theside cover being contiguous to the rear wheel suspension.

[0008] As the side cover is disposed so as to face the air dischargeport, air discharged from the radiator can be drawn out of the airdischarge port by ram air that flows along a side surface of the sidecover. Because the side cover is disposed so as to be contiguous to therear wheel suspension, the side cover and the rear wheel suspension arehighly blended with each other for an improved appearance.

[0009] According to a second aspect of the invention, in addition to thefirst aspect, the side cover covers accessories of the engine.

[0010] Since the side cover covers accessories of the engine,accessories such as an engine control unit, an ignition unit, etc. arenot exposed out, resulting in a further improved appearance.

[0011] According to a second aspect of the invention, in addition to thefirst aspect, the side cover projects laterally of the vehicle body froma side surface of the fuel tank as viewed in plan. Because the sidecover projects laterally of the vehicle from a side surface of the fueltank, a leg of the rider of the motorcycle can be applied to the sidecover. If the leg is shifted inwardly, then the leg can also be appliedto the fuel tank in addition to the side cover, and the force of the legcan be distributed and borne by the fuel tank and the side cover, andthe rider can hold the vehicle frame differently depending on the ridingposture of the rider.

[0012] For a more complete understanding of the present invention, thereader is referred to the following detailed description section, whichshould be read in conjunction with the accompanying drawings. Throughoutthe following detailed description and in the drawings, like numbersrefer to like parts.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a perspective view of a motorcycle incorporating an airdischarge structure according to an embodiment of the present invention;

[0014]FIG. 2 is a side elevational view of the motorcycle according tothe present invention;

[0015]FIG. 3 is a top plan view of the motorcycle according to thepresent invention;

[0016]FIG. 4 is a first perspective view showing a side cover and itssurrounding parts according to the present invention;

[0017]FIG. 5 is a second perspective view showing a side cover and itssurrounding parts according to the present invention;

[0018]FIG. 6 is a cross-sectional view of a fuel tank and side coversaccording to the present invention;

[0019]FIG. 7 is a cross-sectional view of an air discharge structureaccording to another embodiment of the present invention; and

[0020]FIG. 8 is a side elevational view showing a conventional airdischarge structure for a motorcycle.

DETAILED DESCRIPTION OF THE INVENTION

[0021] Embodiments of the present invention will be described below withreference to the drawings. The drawings should be viewed in thedirection in which the reference numerals look normal.

[0022]FIG. 1 is a perspective view of a motorcycle incorporating an airdischarge structure according to the present invention. A motorcycle 10is an American-type motorcycle suitable for long touring, having a frontfork 11 which is inclined greatly to position a handle 12 mounted on anupper portion of the front fork 11, rearwardly with respect to a vehiclebody, and a seat 13 which is of a low height and steps 14 (only the step14 on the viewer's side is shown) positioned more forwardly with respectto the vehicle body, so that the rider of the motorcycle can take acomfortable riding posture.

[0023]FIG. 2 is a side elevational view of the motorcycle according tothe present invention. The motorcycle 10 has a main frame 17 extendingobliquely rearwardly downwardly from a head pipe 16, a fuel tank 21mounted on an upper portion of the main frame 17, a horizontally opposedengine 22 mounted on a lower portion of the main frame 17, a radiator 23mounted on a lower front portion of the main frame 17 forwardly of theengine 22, a radiator cover 24 covering opposite side areas and an upperarea of the radiator 23, and side covers 27 (only the side cover 27 onthe viewer's side is shown) disposed in facing relation to an airdischarge port 26 defined in the radiator cover 24 and covering oppositeside areas between the fuel tank 21 and the engine 22 rearwardly of theradiator cover 24.

[0024] The reference numeral 31 represents a front wheel connected tothe front fork 11 by a link mechanism 32, 33 a front fender covering anupper portion of the front wheel 31, 34 a head lamp, 35, 36 an exhaustpipe and a muffler which are connected to a lower portion of the engine22, 38 a rear wheel vertically movably mounted by a swing arm (notshown) on a rear wheel suspension 41 mounted on a lower portion of themain frame 17, 42 a rear fender covering an upper portion of the rearwheel 38, and 43 an engine guard disposed forwardly of the engine 22.

[0025] The side covers 27 cover engine accessories such as an enginecontrol unit, an ignition unit, etc., and a carburetor which aredisposed above the engine 22 and below the fuel tank 21. The side covers27 are disposed contiguously to the main frame 17 so as to be blendedtherewith for an improved appearance. The head pipe 16, the main frame17, and the rear wheel suspension 41 serve as members of a vehicle frame45.

[0026]FIG. 3 is a plan view of the motorcycle according to the presentinvention, the view showing the motorcycle schematically. Air flows inpatterns that are symmetrical on left and right sides of the vehiclebody, and only the air flow on one side is illustrated for convenience.The motorcycle 10 has the side covers 27 disposed below opposite sidesof the fuel tank 21, and the radiator cover 24 is disposed forwardly ofthe side covers 27. The reference numeral 46 denotes an air inlet portof the radiator cover 24, and 47 the rider of the motorcycle 10.

[0027] While the motorcycle 10 is running, part of the ram air entersthe radiator cover 24 from a side of the front wheel 31, passes throughthe radiator 23, and flows out from the air discharge port 26 of theradiator cover 24.

[0028] The ram air also passes from the side of the front wheel 31alongside of the radiator cover 24, flows along the surface of the sidecover 27, passes through a side of a leg 48 of the rider 47, and flowsrearwardly of the vehicle body.

[0029] At this time, the discharged air flowing out from the airdischarge port 26 is drawn laterally from the radiator cover 24 by apressure drop due to the flow of the ram air alongside of the side cover27. Therefore, the discharged air can flow out in an increased amountfrom the air discharge port 26. Therefore, an excessive temperature risein the radiator cover 24 is prevented from being developed.

[0030]FIG. 4 is a first perspective view showing the side cover and itssurrounding parts according to the present invention. The arrow (front)in FIG. 4 represents a forward direction of the vehicle body (this holdstrue also for other figures).

[0031] The side cover 27 has an upper surface 51 which is curved so asto be convex substantially upwardly, a side surface 52 which is curvedso as to be concave inwardly, and a front surface 53. The discharged airflowing from the air discharge port 26 (see FIG. 2) of the radiatorcover 24 impinges upon the front surface 51 and changes its directionlaterally obliquely rearwardly, as indicated by the arrow (1), and isdrawn out by ram air which flows laterally of the radiator cover 24along the side surface 52 of the side cover 27 as indicated by the arrow(2).

[0032]FIG. 5 is a second perspective view showing the side cover and itssurrounding parts according to the present invention. The radiator cover24 has flow regulating plates 55 (represents a plurality. This holdstrue also for other instances). While the motorcycle is running, airflows indicated by the arrows (3) through (6) are produced around theradiator cover 24 and the side cover 27. Specifically, the arrow (3)represents ram air flowing from above the radiator cover 24 along theupper surface 51 of the side cover 27. The arrow (4) representsdischarged air flowing from the air discharge port 26 along the uppersurface 51. The arrow (5) represents discharged air flowing from the airdischarge port 26 along the front surface 53. The arrow (6) representsram air flowing laterally of the radiator cover 24 along the sidesurface 52 of the side cover 27.

[0033]FIG. 6 is a cross-sectional view of the fuel tank and the sidecovers according to the present invention. The side covers 27,specifically, crest portions 27 a at the boundaries between the uppersurfaces 51 and the side surfaces 52 of the side covers 27, project adistance P laterally of the vehicle body from crest portions 56 of sidesurfaces of the fuel tank 21, and the rider 47 has its legs whose innersides are applied to the side covers 27, respectively. Therefore, theside covers 27 can be held by the respective legs 48. If the legs 48 areforcibly shifted inwardly, then the sides of the fuel tank 21 as well asthe side covers 27 can be held by the legs 48. The force with which thesides of the fuel tank 21 as well as the side covers 27 are held can bedistributed to the fuel tank 21 and the side covers 27. Therefore, withthe motorcycle 10 according to the present invention, only the sidecovers 27 may be held by the legs 48 or both the side covers 27 and thefuel tank 21 may be held by the legs 48, depending on the ridingattitude of the rider 47.

[0034] The reference numeral 57 represents an engine control unit as anaccessory for controlling the supply of the fuel to the engine, ignitiontiming, etc., and 58 an ignition unit as an accessory for enabling sparkplugs to produce sparks. The engine control unit 57 and the ignitionunit 58 are covered by the side covers 27. Since the engine control unit57 and the ignition unit 58 are covered by the side covers 27, they arenot exposed out, so that the appearance of the motorcycle can beimproved.

[0035]FIG. 7 is a cross-sectional view of an air discharge structureaccording to another embodiment of the present invention, the viewshowing a body front cover 60 which includes an integral combination ofa radiator cover and a side cover. The body front cover 60 includes aradiator cover member 62 covering side areas and an upper area of theradiator 23 and having an air discharge port 61, and a side cover member63 integrally formed with a rear portion of the radiator cover member62. The radiator cover member 62 and the side cover member 63 have thesame functions as the radiator cover 24 (see FIG. 2) and the side covers27 (see FIG. 2). The reference numeral 65 represents an air inlet portof the body front cover 60, and 66 a rear opening of the body frontcover 60.

[0036] The arrows in FIG. 7 show air flows from the body front cover 60and the air discharge port 61. The broken-line arrows show air that isnot discharged from the air discharge port 61 of the body front cover60, but is directed in the side cover member 63 toward the rear portionof the vehicle body, the air flowing out from the rear opening.

[0037] As described above with reference to FIGS. 2 and 3, according toa first feature of the present invention, the motorcycle 10 has thefront wheel 31 suspended on a front portion of the vehicle frame 45, therear wheel 38 suspended by the rear wheel suspension 41 mounted on arear portion of the vehicle frame 45, the fuel tank 21 mounted on anupper portion of the vehicle frame 45, the engine 22 mounted on a lowerportion of the vehicle frame 45, the radiator 23 disposed forwardly ofthe engine 22, and the radiator cover 24 covering the radiator 23 andhaving the air discharge port 26 for discharging air from the radiator23 rearwardly of the vehicle frame, characterized in that the sidecovers 27 are disposed in a position facing the air discharge port 26,i.e., rearwardly of the air discharge port 26, and cover both side areasbetween the fuel tank 21 and the engine 22, the side covers 27 beingcontiguous to the main frame 17 and the rear wheel suspension 41.

[0038] As the side covers 27 are disposed so as to face the airdischarge port 26, air discharged from the radiator 23 can be drawn outof the air discharge port 26 by ram air that flows along a side surfaceof the side covers 27. Therefore, the discharged air can flow out fromwithin the radiator cover 24 in an increased amount, and an excessivetemperature rise in the radiator cover 24 is prevented from beingdeveloped.

[0039] Because the side covers 27 are disposed so as to be contiguous tothe rear wheel suspension 41, the side covers 27 and the rear wheelsuspension 41 are highly blended with each other for thereby improvingthe appearance of the American-type motorcycle 10 in particular.

[0040] According to a second feature of the present invention, the airdischarge structure is characterized in that the side covers 27 coveraccessories of the engine 22 as shown in FIGS. 2 and 6. Since the sidecovers 27 cover accessories of the engine 22, e.g., the engine controlunit 57 and the ignition unit 58, the engine control unit 57 and theignition unit 58 are not exposed out, resulting in a further improvedappearance.

[0041] According to a third feature of the present invention, the airdischarge structure is characterized in that the crest portions 27 a ofthe side covers 27 project laterally of the vehicle body from the crestportions 56 of side surfaces of the fuel tank 21 as viewed in plan. Thecrest portions 27 a of the side covers 27 project laterally of thevehicle body from the crest portions 56 of the side surfaces of the fueltank 21. Therefore, the legs 48 of the rider 47 can be applied to theside covers 27, respectively. If the legs 48 are shifted inwardly, thenthe legs 48 can be applied to the fuel tank 21 as well as the sidecovers 27. The force of the legs 48 can be distributed to the fuel tank21 and the side covers 27, and the vehicle body can be held by the legsdifferently depending on the riding attitude of the rider. Since theriding attitude has more freedom, the motorcycle 10 (see FIG. 2) can behandled with increased ease.

[0042] The side covers according to the present invention may becontiguous to the radiator cover.

[0043] With the above arrangement, the present invention offers thefollowing advantages:

[0044] The air discharge structure for the motorcycle according to thefirst aspect of the invention resides in that the side cover is disposedin a position facing the air discharge port and covers a side areabetween the fuel tank and the engine, the side cover being contiguous tothe rear wheel suspension. Therefore, air discharged from the radiatorcan be drawn out of the air discharge port by ram air that flows along aside surface of the side cover. Therefore, the discharged air can flowout from within the radiator cover in an increased amount, and anexcessive temperature rise in the radiator cover is prevented from beingdeveloped.

[0045] Because the side cover is disposed so as to be contiguous to therear wheel suspension, the side cover and the rear wheel suspension arehighly blended with each other for thereby improving the appearance ofan American-type motorcycle in particular.

[0046] The air discharge structure for the motorcycle according to thesecond aspect of the invention resides in that the side cover coversaccessories of the engine 22. The accessories, e.g., the engine controlunit, the ignition unit, etc., are not exposed out, resulting in afurther improved appearance.

[0047] The air discharge structure for the motorcycle according to thethird aspect of the invention resides in that the side cover projectslaterally of the vehicle body from side surfaces of the fuel tank asviewed in plan. Therefore, a leg of the rider of the motorcycle can beapplied to the side cover. If the leg is shifted inwardly, then the legcan also be applied to the fuel tank in addition to the side cover, andthe force of the leg can be distributed and borne by the fuel tank andthe side cover, and the rider can hold the vehicle frame differentlydepending on the riding posture of the rider.

[0048] Although the present invention has been described herein withrespect to specific illustrative embodiments thereof, the foregoingdescription is intended to be illustrative, and not restrictive. Thoseskilled in the art will realize that many modifications of theembodiments could be made which would be operable. All suchmodifications which are within the scope of the claims are intended tobe within the scope and spirit of the present invention.

What is claimed is:
 1. An air discharge structure for a motorcyclehaving a front wheel suspended on a front portion of a vehicle frame, arear wheel suspended by a rear wheel suspension mounted on a rearportion of the vehicle frame, a fuel tank mounted on an upper portion ofthe vehicle frame, an engine mounted on a lower portion of the vehicleframe, a radiator disposed forwardly of the engine, and a radiator covercovering the radiator and having an air discharge port for dischargingair from the radiator rearwardly of a vehicle body, wherein: a sidecover is disposed in a position facing said air discharge port andcovers a side area between said fuel tank and the engine, said sidecover being contiguous to said rear wheel suspension.
 2. An airdischarge structure for a motorcycle according to claim 1, wherein saidside cover covers accessories of said engine.
 3. An air dischargestructure for a motorcycle according to claim 2, wherein saidaccessories of said engine include at least one of an engine controlunit and an ignition unit.
 4. An air discharge structure for amotorcycle according to claim 1, wherein said side cover projectslaterally of the vehicle body from a side surface of said fuel tank asviewed in plan.
 5. An air discharge structure for a motorcycle accordingto claim 2, wherein said side cover projects laterally of the vehiclebody from a side surface of said fuel tank as viewed in plan.
 6. An airdischarge structure for a motorcycle according to claim 1, including apair of said side cover disposed on opposite sides of said motorcycle.7. An air discharge structure for a motorcycle according to claim 1,wherein said side cover and said radiator cover are formed as anintegral unitary member.
 8. An air discharge structure for a motorcycleaccording to claim 7, wherein said air discharge port is defined in saidintegral unitary member between said radiator cover and said side cover.9. An air discharge structure for a motorcycle according to claim 1,wherein said side cover has an upper surface curved convex substantiallyupwardly, a side surface curved concave inwardly and a front surface.10. An air discharge structure for a motorcycle according to claim 9,wherein said side cover a crest portion at a boundary between said upperand side surfaces, said crest portion projects laterally of the vehiclebody from a side surface of said fuel tank as viewed in plan.
 11. Amotorcycle comprising: a front wheel suspended on a front portion of avehicle frame; a rear wheel suspended by a rear wheel suspension mountedon a rear portion of the vehicle frame; a fuel tank mounted on an upperportion of the vehicle frame; an engine mounted on a lower portion ofthe vehicle frame; a radiator disposed forwardly of the engine; aradiator cover covering the radiator and having an air discharge portfor discharging air from the radiator rearwardly of a vehicle body; anda side cover disposed in a position facing said air discharge port andcovering a side area between said fuel tank and the engine, said sidecover being contiguous to said rear wheel suspension.
 12. A motorcycleaccording to claim 11, wherein said side cover covers accessories ofsaid engine.
 13. A motorcycle according to claim 12, wherein saidaccessories of said engine include at least one of an engine controlunit and an ignition unit.
 14. A motorcycle according to claim 11,wherein said side cover projects laterally of the vehicle body from aside surface of said fuel tank as viewed in plan.
 15. A motorcycleaccording to claim 12, wherein said side cover projects laterally of thevehicle body from a side surface of said fuel tank as viewed in plan.16. A motorcycle according to claim 11, including a pair of said sidecover disposed on opposite sides of said motorcycle.
 17. A motorcycleaccording to claim 11, wherein said side cover and said radiator coverare formed as an integral unitary member.
 18. A motorcycle according toclaim 17, wherein said air discharge port is defined in said integralunitary member between said radiator cover and said side cover.
 19. Amotorcycle according to claim 11, wherein said side cover has an uppersurface curved convex substantially upwardly, a side surface curvedconcave inwardly and a front surface.
 20. A motorcycle according toclaim 19, wherein said side cover a crest portion at a boundary betweensaid upper and side surfaces, said crest portion projects laterally ofthe vehicle body from a side surface of said fuel tank as viewed inplan.